The AfterShokz Sports M2 headphones are unlike any headphones you've ever used - unless you've previously used bone-conduction headphones, that is. The Sports M2's are the most recent wrap-around headphone offering from bone-conduction headphone company AfterShokz, and are also sweat- and water-resistant. See also: AfterShokz Mobile review.

AfterShokz Sports M2: Fitness level

The good thing about headphones is that they're designed for people of any fitness level. The Sportz M2 headphones will work for everyone--especially people with oddly-shaped ears or inconvenient piercings, since they don't actually sit on or inside the ear. The wrap-around style can be a challenge for those who wear glasses however, as the stem of the headphones rests on the same part of the ear as eyeglasses do.

AfterShokz Sports M2: Best activities

Bone-conduction headphones are typically intended for listening in loud environments. Thus, the Sportz M2 headphones are best for outdoor activities, including jogging, running, biking, and hiking. The open-ear design lets you hear ambient noise (such as traffic), but does a poor job of masking the music you're listening to. So, great for outdoors, but not ideal for quiet indoor spaces.

AfterShokz Sports M2: Design and features

The Sportz M2 headphones are similar in design to the previous model. They feature a black, light-weight frame that wraps around your neck and hooks over your ears. At the end of the frame there are small, rubbery bone-conduction pads that rest on your cheekbones. The left side of the frame features the thin wire connection, while the back has a small reflection strip.

If you've never worn bone-conduction headphones before, let me explain how they work: The headphones pump music to the bone-conduction pads, which sit on your cheekbones right in front of your ears. The pads then pulsate, pumping music through the bones of your face into your inner ear. The result: You hear decent-sounding music without having to worry about anything covering, or plugging, your ears.

The open-ear design means you can also hear ambient noise around you (like traffic or people talking) while listening to your music. Of course, there's a limit to how much ambient noise you can hear--if you pump up your music too much, you won't be able to hear anything. The catch to the open-ear design is that it doesn't conceal the music you're listening to very well, so these headphones are not a great choice for quiet environments (such as libraries).

The M2s are noticeably lighter than their predecessors--about 30 percent lighter, according to the company. This means they're a little more comfortable and less noticeable when you're wearing them, though the rigid plastic neck band still gets in the way if you're lying on the floor or on a bench. This isn't too much of a problem, however, since the headphones are better for outdoor workouts.

The headphones are powered by a small battery pack that clips to your shirt. The battery pack has a power switch, volume buttons, a call button (that doubles as a play/pause button), and a microphone for taking phone calls. Call quality is fairly good, though people on your end will be able to hear both sides of the conversation. In my tests, people on the other line reported crisp, clear voice reception.

The battery pack also has a Micro-USB port, which is a big improvement over the previous generation's special USB charger. A full charge will get you about 15 hours of playback at a moderate volume level.

The biggest drawback of the Sportz M2 headphones is the sound quality: it's way below average. Don't get me wrong--it's actually much better than the sound quality of the first-generation headphones, which had muddy midtones and literally no bass beat to speak of. The M2s actually have a nice, semi-thumpy bass beat, but their sound quality is about on par with £20 supermarket headphones. That said, these headphones are not really designed for sound quality--they're designed for people who are interested in maintaining audio contact with the outside world. Read our audio buying advice.

AfterShokz Sports M2: The bottom line

If you care about how your music sounds, I'd advise you to stay away from AfterShokz' line of bone-conduction headphones. Bone-conduction technology just doesn't give the bass beat that audiophiles crave-mostly because it's not designed to. Instead, these headphones are for people who are active in loud, potentially dangerous environments,for example, joggers on a crowded street or cyclists who want to hear the traffic around them. They've also been proven useful for those who may have problems with their ears: According to the company, users who were deaf in one ear were able to hear in surround-sound using the AfterShokz' because it bypasses the ear canal.

Assuming you're part of AfterShokz' niche market, the Sportz M2 headphones are a nice improvement over the previous generation. They're lighter, more comfortable, with a better-designed remote and better sound quality, and they come with a nice hard zip case (unlike the previous model's velvet bag) to keep them safe. See also: Group test - what are the best headphones?

The AfterShokz Sport range of headphones sit on, rather than in, the ear, meaning that joggers can enjoy their favourite tunes and still hear ambient noises such as oncoming traffic, car horns and so on. Here's our AfterShokz Mobile review.

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